Hair grows on human skin in various textures, colors, and density. The structure from which each hair grows is called a follicle. Muscles, oil glands (sebaceous glands), and nerves extend from the follicle into the next layer of the skin—the dermis. Throughout life, the skin is constantly shedding dead skin cells and growing new ones. This happens all over the skin. Inside the follicles, sebum (oil) carries the dead cells to the surface. Various factors can interfere with the cycle of renewal and disposal, and a number of disorders can result.
Skin Follicle diseases include infectious diseases, immunological disorders, blockage of sebaceous gland or of all hair follicle, cancers, and multiple cause inflammatory conditions.
Folliculitis is the infection and inflammation of the hair follicles. The condition may be superficial (i.e., on the surface of the skin) or deep within the follicles. Hair follicles become red and irritated, and pus-filled lesions form. Folliculitis can clear up by itself in a matter of a couple of weeks or become more persistent and thus require treatment. The most common cause of folliculitis is infection by the bacteria Staphylococcus aureus. Other species of bacteria may also be responsible. For example, contaminated water in whirlpools and hot tubs can transmit Pseudomonas aeruginosa, which can cause folliculitis. This bacterium may also be passed in wet suits. Fungal and viral infections can also cause the condition. These are not common, but doctors may suspect these agents if conventional treatments do not work. Viral infections may be more common in those with compromised immune systems, such as AIDS, organ transplant, and cancer patients.
Folliculitis symptoms can appear independent of infection. Exposure of the skin to certain chemicals, especially oils and tars, can trigger an outbreak. People with depressed immune systems, diabetes, or obesity have a greater risk of contracting folliculitis than the general population. An early sign of folliculitis is a small white or yellow pus-filled lesion (pustule) on a red, inflamed follicle. The most likely starting points are the scalp, thighs, legs, and buttocks. When an infection of the follicle goes deeper, it becomes a boil or furuncle. A group of closely packed boils create a larger lesion called a carbuncle. These lesions tend to occur in hairy, sweaty areas of the body.
Hidradenitis suppurativa is a potentially serious, chronic, pus-producing (suppurative) disorder of the follicles and sweat glands. Hidradenitis suppurativa develops primarily in the sweat glands located in the armpits, in the groin, around the breasts, and in the anal region. The follicles and ducts become blocked, and bacteria and pus are forced into the surrounding tissue, causing irritation. Abscesses form and can become quite large and eventually break through the skin. Abscesses may open and drain spontaneously. Scar tissue forms in the healing process. Hidradenitis suppurativa can be a socially and physically painful and disabling disease. The bacterium Staphylococcus aureus is usually involved in the condition, and Proteus species are often involved in chronic cases. Bacteria called coagulase-negative staphylococci (CNS) have also been associated with these infections.
There seems to be a genetic predisposition for the disease, and it seems to be more common in women. Hidradenitis suppurative does not appear in people who have not reached puberty because the sweat glands are not active, but it can appear at any age afterward. Hidradenitis suppurativa affects people who are extremely overweight (obese) at a higher rate than the general population. Cigarette smokers also have a higher incidence of this disorder than nonsmokers.
Signs of hidradenitis are firm red nodules that are usually located under the arm, in the groin, around the breasts, or around the anus. Pustules and abscesses may discharge pus spontaneously and heal slowly, resulting in scar tissue. The appearance of nodules recurs periodically throughout the year. Heat, perspiration, and being overweight can aggravate the condition. Pain is a common symptom in chronic disease. Over time, fibers of scar tissue branch out, creating restrictive, tight skin. This can interfere with movement of the arms or legs, if the sweat glands in the armpits or groin are involved. Dermatologists diagnose the disorder by the appearance and location of the lesions. Infection and inflammation can spread beyond the sweat glands into cells located in the deep layers of the skin and in muscle tissue. This condition is called cellulitis. The skin covering the infected area is usually warm and tender.
Keratosis pilaris is a condition in which the hair follicles become blocked with hair and dead cells from the outermost layer of skin (epidermis). The follicles redden and inflame causing bumps (papules) to develop. The papules of keratosis pilaris usually occur on the upper arms and thighs, but also appear on the face, back, and buttocks.
Keratosis pilaris (KP) is a hereditary disorder. One can inherit it from one or both parents. KP stems from overreproduction of keratinocytes, the cells that manufacture the protein keratin, an important skin component (called hyperkeratosis). Some researchers describe KP as one of a whole spectrum of disorders, rather than as an independent disease. KP is more prevalent among children and adolescents and less common in adults. It seems to improve after puberty. Individuals with dry skin and eczema (skin disorder) tend to have more severe cases. The condition improves during warm summer months and worsens during the winter. The signs of keratosis pilaris are the papules that typically appear on the upper arms and thighs, and sometimes on the back, face, and buttocks. Papules re-form after they have been removed.
Perioral dermatitis (POD) is a disorder of the follicles in which pink bumps (papules) appear around the mouth and sometimes around the eyes. POD is most common in 20- to 50-year-old women, but occurs in men and children as well. The causes of POD are not well understood. There is some evidence that fungi and bacteria may be underlying causes of the disorder. However, this has not been proven.
People who use topical corticosteroids (anti-inflammatory drugs) for other skin disorders on the face have a higher rate of POD than the general population. Stress also plays a role, as does repeatedly touching the skin on the face. Dermatologists usually diagnose POD by the occurrence of pink papules around the mouth. Often the papules develop around the eyes and nostrils as well. The next stage of POD brings scaling and reddening. Some patients experience burning and itching. POD has a tendency to improve and worsen at variable intervals.
Rosacea is a disorder of the follicles and surrounding skin that usually occurs on the forehead, nose, and chin. It involves reddening, acnelike lesions, and broken blood vessels. Rosacea improves and worsens in unpredictable cycles. The exact cause is unknown. Although rosacea can appear at any age, it is most prevalent between 30 and 60 years old. It occurs about equally in men and women, although severe cases are more common in men. Rosacea seems to have a genetic component. Individuals whose family members have rosacea have a higher incidence of the disorder. Emotional and physical stress, windy conditions, heat, and sun exposure can exacerbate rosacea. Dietary triggers include dairy products, certain spices, hot liquids, and alcohol.
Some people with stomach ulcers are prone to develop rosacea. The cause of a high percentage of stomach ulcers is infection with the bacterium Heliobacter pylori (H. pylori). While studies are still inconclusive, eradication of H. pylori in ulcer patients can lead to improvement in rosacea. There is increasing evidence that this bacterium causes a variety of systemic disorders. However, rosacea appears without H. pylori and vice versa.
Doctors usually diagnose rosacea by observing the appearance of the skin. Not all redness, flushing, and blushing is caused by rosacea. However, redness that takes a long time to clear up, or never clears up, often indicates rosacea. Acne pustules sometimes develop with this condition; however, blackheads are not a hallmark. Bacterial infections can contribute to inflammation. As the disorder progresses, the patient's facial skin exhibits broken blood vessels. A rare symptom is rhinophyma, a thick, leathery texture of the nose skin. The eyes can be affected with irritation and increased light sensitivity.
Acne is also a hair follicle disease whereas follicles are finally clogged and become infected and inflamed. Acne is an inflammatory skin disorder of the skin's sebaceous glands and hair follicles that affects about 80% of people between the ages of 12 and 24. There is a genetic propensity for follicular epidermal hyperproliferation with subsequent plugging of the follicle. Retention hyperkeratosis is the first recognized event in the development of acne vulgaris. Excess sebum is another key factor in the development of acne vulgaris. Sebum production and excretion are regulated by a number of different hormones and mediators. P acnes is an anaerobic organism present in acne lesions. The presence of P acnes promotes inflammation through a variety of mechanisms. P acnes stimulates inflammation by producing proinflammatory mediators that diffuse through the follicle wall.
Alopecia is a condition affecting humans, in which hair is lost from some or all areas of the body, usually from the scalp. Alopecia may occure as consequence of genetics or following chemotherapy and radiation. Treating or preventing of common Alopecia and treating chemotherapy induced alopecia may be achieved with hair growth stimulators that are generally well known, and include minoxidil, substance-P, cyclosporin, cyclosporin A, finesteride, and the like known hair growth stimulators.
The primary principle behind laser hair removal is selective photothermolysis (SPTL) Lasers can cause localized damage by selectively heating dark target matter, (melanin), in the area that causes hair growth, (the follicle), while not heating the rest of the skin. Light is absorbed by dark objects, so laser energy can be absorbed by dark material in the skin (but with much more speed and intensity). This dark target matter, or chromophore, can be naturally-occurring or artificially introduced.
Hair removal lasers selectively target melanin: Melanin is considered the primary chromophore for all hair removal lasers currently on the market. Melanin occurs naturally in the skin (it gives skin and hair its color). There are two types of melanin in hair: eumelanin (which gives hair brown or black color) and pheomelanin (which gives hair blonde or red color). Because of the selective absorption of photons of laser light, only black or brown hair can be removed.
Both men and women seek laser hair removal services to have superfluous or unwanted hair removed. Hair removal is commonly done on lip, chin, ear lobe, shoulders, back, underarm, abdomen, buttocks, pubic area, bikini lines, thighs, face, neck, cleavage, chest, arms, legs, hands, and toes. Laser works best with dark coarse hair. Light skin and dark hair are an ideal combination, but new lasers are now able to target dark black hair even in patients with dark skin
However, Laser hair removal of blond and white hair is a complicated task with often unsatisfactory results as a result of a lack of laser-absorbing chromophore. Attempts to introduce Liposome encapsulated melanin (Lipoxome; Dalton Medicare B. V., Zevenbergschen Hoek, The Netherlands) into the hair follicles were not successful. (Ann Plast Surg. 2007 May; 58(5):551-4. (A randomized, controlled, double-blind study evaluating melanin-encapsulated liposomes as a chromophore for laser hair removal of blond, white, and gray hair. Sand M, Bechara F G, Sand D, Altmeyer P, Hoffmann K.)
White gray or blond hair does not respond effectively to Laser selective photothermolysis treatment and thus pose an unmet need. Practically, people suffering from unwanted non-pigmented hair grow (white, gray or light blond) could not be effectively treated with photothermolysis. Attempts to artificially introduce melanin into the hair follicle by Liposome melanin require many applications each day over few days whereas pigmenting the hair follicles with current application by various pigments occurs within one day and one to three single applications.
Lingna and Valeryi U.S. Pat. Nos. 5,914,126 and 5,753,263 disclose liposomes that target preferentially hair follicle. However liposomes are difficult to produce and to stabilize and have limited loading capacity and very low unfavorable loading yield, making them inferior for industrial production.
There is therefore a need for a vehicle or carrier which is a delivery system that will effectively deliver drugs or cosmetic agents to the hair follicle cavity, that will be simple to produce and develop, have high load and yield and provide effective hair follicle targeting and accumulation.